Add documentation for Spectral rules

[rocketstack-matt]

Feature Request

Description of Problem:

Spectral rules which raise warnings or errors can be a little verbose. It would be good to provide richer documentation for people to understand what the messages mean / give additional context.

Potential Solutions:

Per the Spectral documentation you can specify a URL which is a location providing more detail / human readable rules. Each rule can act as an anchor link will provide direct link to documentation from the rules that are triggered.